/*
 * XADXORHandle.m
 *
 * Copyright (c) 2017-present, MacPaw Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301  USA
 */
#import "XADXORHandle.h"

@implementation XADXORHandle

-(id)initWithHandle:(CSHandle *)handle password:(NSData *)passdata
{
	if((self=[super initWithParentHandle:handle]))
	{
		password=[passdata retain];
		passwordbytes=[password bytes];
		passwordlength=[password length];
	}
	return self;
}

-(id)initAsCopyOf:(XADXORHandle *)other
{
	[self _raiseNotSupported:_cmd];
	return nil;
}

-(void)dealloc
{
	[password release];
	[super dealloc];
}



-(off_t)fileSize { return [parent fileSize]; }

-(off_t)offsetInFile { return [parent offsetInFile]; }

-(BOOL)atEndOfFile { return [parent atEndOfFile]; }

-(void)seekToFileOffset:(off_t)offs { [parent seekToFileOffset:offs]; }

-(void)seekToEndOfFile { [parent seekToEndOfFile]; }

-(int)readAtMost:(int)num toBuffer:(void *)buffer
{
	off_t pos=[parent offsetInFile];
	int actual=[parent readAtMost:num toBuffer:buffer];

	if(passwordlength)
	{
		uint8_t *buf=(uint8_t *)buffer;
		for(int i=0;i<actual;i++) buf[i]^=passwordbytes[(pos+i)%passwordlength];
	}

	return actual;
}

@end
